Edward - "like" is a Facebook convention, if say you post that you had a great lunch, you circle of friends can click on the 'Like' button next to your post. I personally think 'like' button turns communication into obligatory clicks instead of thoughtful textual replies
The "Poll" function is available - that is enough functionality for anyone who is trying to gauge preferences.
And of course we already have the "SuperDislike" button - the "Report to Moderators" function!
“Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”
Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2